The characterization of a telecommunications device's parametric performance is a vital aspect of the product development, verification and acceptance process. Proper parametric characterization will reveal hardware and software faults that may have a substantial effect of the product performance that might otherwise go unnoticed until the equipment is deployed in the field. Historically, the execution of a parametric test suite on first and second generation linear amplifiers has been relatively simple, primarily because of the low crest factors of the signals involved and the single carrier per amplifier base station architecture. The nature of transmitter test methodologies changed substantially with the introduction of high crest factor modulation schemes such as CDMA and OFDM, and will change further as the communications industry continues moving toward multicarrier amplifier schemes.
Historically, the measurement of transmitter output power was a relatively simple matter. The constant-envelope modulation schemes used in first-generation analog equipment allowed the use of simple square-law detectors or thermal power measurement devices. The introduction of non constant-envelope digital modulation in TDMA systems complicated the measurement of output power slightly, however, this was easily accommodated by test equipment manufacturers because of the relatively low peak to average power ratio.